Who’s Side Would You Take: Your Spouse or Your Sibling? [POLL]

A friend of mine has a brother that is getting ready to turn 30.  Six months ago, she purchased tickets to see the Red Hot Chili Peppers at the Sprint Center in Kansas City on October 27.  She was planning on them going to the show together.

He IS married and it seems he and his wife now have plans on that date, even though his spouse knew about these tickets WELL in advance.  Now she doesn't want him to go and accept his birthday present from his sister.   I've been invited to attend the concert if it turns out he can't go.

I grew up with an older brother and a sister.  My sister and I were estranged at the time of her death.  My closest friends will read that and drop their jaws.  It isn't something I talk about often.  But it IS germane to my point.  Nobody should come between two siblings.  Their relationship is a special life long relationship and should be cherished.

Boyfriends/girlfriends and even marriages may come and go, but the deep ties of brotherhood/sisterhood cannot truly be uprooted.    What do you think?